It's a press fit........with dissimilar metals.......in a high torque location.

My advice would be to reexamine your own assumptions with regard to
what you are and are not capable of doing with a dremel or a file.

Then either be happy with your results or keep looking for the correct
spindle. They can be difficult to come up with. Look for a nearby coop
or other boneyard and look at the crapped out MTB's with tapered spindle
BB's. At one time they were all over the place, now not so much.